Laser ablation in liquid (LAL) has received considerable attention over the last decade, and is gradually becoming an irreplaceable technique to synthesize nanocrystals and fabricate functional ...nanostructures because it can offer effective solutions to some challenges in the field of nanotechnology. The goal of this review is to offer a comprehensive summary of recent developments of LAL in nanocrystal synthesis and nanostructure fabrication. First, we will introduce the fundamental processes of microsecond, nanosecond, and femtosecond LAL, and how the active species act differently in plasma, cavitation bubbles, and droplets in the different LAL processes. Second, a variety of LAL-based techniques for nanomaterials synthesis and processing are presented, such as electric-, magnetic-, and temperature-field LAL, as well as electrochemically assisted LAL, pulsed laser deposition in liquid, and laser writing of nanopatterns in liquid. Third, new progress in LAL-generated nanomaterials is described. Fourth, we emphasize five applications of LAL-generated nanomaterials that have emerged recently in the fields of optics, magnetism, environment, energy, and biomedicine. Finally, we consider the core advantages of LAL, the limitations of LAL and corresponding solutions, and the future directions in this promising research area.
Summary
Inter‐vascular transfer in rice (Oryza sativa) nodes is required for delivering mineral elements to developing tissues, which is mediated by various transporters in the nodes. However, the ...effect of these transporters on distribution of mineral elements in the nodes at a cellular level is still unknown. Here, we established a protocol for bioimaging of multiple elements at a cellular level in rice node by laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS), and compared the mineral distribution profile between wild‐type (WT) rice and mutants. Both relative comparison of mineral distribution normalized by endogenous 13C and quantitative analysis using spiked standards combined with soft ablation gave valid results. Overall, macro‐nutrients such as K and Mg were accumulated more in the phloem region, while micro‐nutrients such as Fe and Zn were highly accumulated at the inter‐vascular tissues of the node. In mutants of nodal Zn transporter OsHMA2, Zn localization pattern in the node tissues did not differ from that of WT; however, Zn accumulation in the inter‐vascular tissues was lower in uppermost node I but higher in the third upper node III compared with the WT. In contrast, Si deposition in the mutants of three nodal Si transporters Lsi2, Lsi3 and Lsi6 showed different patterns, which are consistent with the localization of these transporters. This improved LA‐ICP‐MS analysis combined with functional characterization of transporters will provide further insight into mineral element distribution mechanisms in rice and other plant species.
Significance Statement
We established a method with laser ablation‐inductively coupled plasma‐mass spectrometry for multi‐elemental imaging at a cellular level in rice node as well as root and leaf tissues. This method is characterized by high‐resolution, easy accessibility, low running cost. Normalization by endogenous 13C makes different samples comparable. Furthermore, combination of spiked cryo‐compound of standards with soft ablation technique gave quantitative results for each element. This technique will be a powerful tool for linking transporter localization to element distribution at a cellular level.
Submarine hydrothermal sulfide ores occur at mid-ocean ridges, intra-oceanic arcs and in back-arc basins associated with host rocks of highly variable composition. Pyrite is the dominant sulfide ...mineral in most samples presented within this study, and thus the trace element composition of pyrite may reflect the different metal sources and precipitation processes. Here, we report on a systematic study of minor and trace element contents in pyrite from active and inactive submarine hydrothermal vent fields at different plate-tectonic settings including the Indian and Mid-Atlantic Ridges, the Tonga–Kermadec intra-oceanic arc, the Lau back-arc and the central Okinawa Trough. Our results show that the trace element contents of pyrite from different locations vary significantly but for most elements without any systematic correlation to the concentration in the magmatic host rocks. Only As appears to be depleted in pyrite from ultramafic-hosted vent systems that are affected by serpentinization. These As depleted pyrites preferentially host Au 0 micro- or nano-particles. Bismuth is enriched in pyrite from hydrothermal systems that contain a sedimentary component and micro-inclusions of sphalerite are either due to fluid–sediment interaction or phase-separated fluid venting. Pyrites from individual locations have highly variable concentrations of elements like Au, Co, Cu, Se, Mo, Ag and Sb that are most likely related to fluid evolution and changes in fluid composition. Sub-seafloor hydrothermal fluid–seawater mixing influences the distribution of Au, Co, Cu, Se and Mo in pyrite. Elements like Au, Ag, Sb and Pb often have a characteristic affinity to As, while Cd correlates closely with Zn. A magmatic volatile contribution to the Hine Hina hydrothermal system may result in the precipitation of Cu-enriched pyrite. Our results show that the concentrations of most trace metals in pyrite are a function of the physicochemical parameters of the fluid phase rather than a reflection of the magmatic host rock composition.
•Global data base of trace element pyrite chemistry.•Most trace elements in hydrothermal pyrite are independent of the magmatic host rock composition.•Fluid–sediment interaction and serpentinization processes affect the composition of hydrothermal pyrite.•Fluid temperature variations control the trace element composition of pyrite.•Phase separation and magmatic volatiles also influence the pyrite composition.
Bimetallic nanoparticles have gained vivid attention due to their unique and synergistic properties. They can be used in fields such as solar cells, optics, sensing, as well as medicine. The ...generation of bimetallic nanoparticles, containing oxide phases of both magnetic and X-ray attenuating metals for bioimaging applications has been challenging with traditional chemical synthesis methods. An alternative is the generation of nanoparticles from binary oxide ceramics by laser ablation in liquid. However, the applicability of this technique for production of hybrid nanoparticles consisting of magnetic and X-ray absorbing elements has not been demonstrated yet.
In this work, novel ceramics composed of bimetallic oxide phases of iron-tantalum, iron-tungsten, and iron-bismuth were produced by a reaction-sintering method. The bulk samples were characterized with scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry. Nanoparticles were produced in aqueous and ethanol solutions by employing a femtosecond laser and characterized with transmission electron microscopy, selected area electron diffraction, and energy dispersive X-ray spectroscopy. The results demonstrated that the production of binary oxide bulk ceramics and their subsequent laser ablation in liquids leads to the successful generation of bimetallic oxide nanoparticles, without a core-shell morphology. In addition, it was found that the ablation threshold fluence of bulk samples as well as the crystallinity of the synthesized nanoparticles is governed by both the nature of the metallic oxide ceramics and the employed liquid. The results pave the way for a single step generation of well-defined bimetallic nanoparticles by laser ablation that could potentially exhibit X-ray and magnetic absorption properties suitable for multimodal imaging applications.
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Although oxide nanoparticles are ubiquitous in science and technology, a multitude of compositions, phases, structures, and doping levels exist, each one requiring a variety of conditions for their ...synthesis and modification. Besides, experimental procedures are frequently dominated by high temperatures or pressures and by chemical contaminants or waste. In recent years, laser synthesis of colloids emerged as a versatile approach to access a library of clean oxide nanoparticles relying on only four main strategies running at room temperature and ambient pressure: laser ablation in liquid, laser fragmentation in liquid, laser melting in liquid and laser defect‐engineering in liquid. Here, established laser‐based methodologies are reviewed through the presentation of a panorama of oxide nanoparticles which include pure oxidic phases, as well as unconventional structures like defective or doped oxides, non‐equilibrium compounds, metal‐oxide core–shells and other anisotropic morphologies. So far, these materials showed several useful properties that are discussed with special emphasis on catalytic, biomedical and optical application. Yet, given the endless number of mixed compounds accessible by the laser‐assisted methodologies, there is still a lot of room to expand the library of nano‐crystals and to refine the control over products as well as to improve the understanding of the whole process of nanoparticle formation. To that end, this review aims to identify the perspectives and unique opportunities of laser‐based synthesis and processing of colloids for future studies of oxide nanomaterial‐oriented sciences.
Laser‐assisted synthesis of colloids emerged as a versatile approach to access a library of oxide nanoparticles and related nanostructures at room temperature and ambient pressure. This review provides a critical presentation of laser‐based methodologies, of the various oxide nanoparticles achieved so far, and of their applications in catalysis, optics, biotechnology and further emerging fields.
Abstract
The demand is growing for new nanoscience-based technologies with unique properties that are different from traditional wet-chemical techniques. In recent years, laser ablation in liquid ...(LAL) has attracted increasing attention for nanomaterial synthesis, which has rapidly advanced both fundamental research and applications. Compared to other techniques, LAL is easy to set up and simple to perform. A large diversity of bulk and powder targets can be employed for LAL, which combined with an enormous variety of liquids, greatly diversify the nanomaterials that can be synthesized by LAL in terms of size, composition, shape, and structure. Although many reviews related to LAL have been published, a comprehensively thorough introduction that deals with the diversity of the targets and liquids used for LAL is still missing. To fill this gap, this review gives a comprehensive summary of the nanomaterials synthesized by LAL using different types of target and liquid, with an emphasis on the effects of liquids on the final nanoproducts. In order to provide a better understanding of the liquids’ effects, this review also discusses liquid additives such as salts, polymers, support materials, and their mixtures. Since many reactions occur during LAL, the scope of reactive laser ablation in liquid (RLAL) is redefined, and the representative reactions for each type of liquid used for LAL are summarized and highlighted. Consequently, this review will be a useful guide for researchers developing desirable nanomaterials via LAL.
Over the last decade, lasers have been gradually employed for Si wafer dicing to replace blade dicing. Laser dicing has the potential to replace blade dicing as the future generation ultrathin wafer ...singulation method as it enables higher cutting speed, lower damage, and smaller kerf width but various technical challenges still remain to be resolved. In this article, laser ablation and dicing of Si wafers are reviewed in terms of the physics of laser-material interaction based on nanosecond, picosecond, and femtosecond pulse durations. The effects of various laser settings, dicing process parameters, and material factors on ablation rate, ablation precision and quality, and die fracture strength are discussed in detail. With the increasing usage of Cu stabilization layer on the backside of ultrathin Si wafers, we also review laser-material interaction in Cu and elaborate on recent findings on the effects of laser dicing through Si and Cu simultaneously on the microstructural and fracture strength properties of the die. Various approaches to improve the ablation rate, ablation quality, and die fracture strength are discussed.
•Laser dicing of thin Si wafers is gaining more importance in the semiconductor industry because of its cost-effectiveness compared to conventional blade dicing.•Understanding laser ablation mechanisms remains a huge challenge because of the complexity of the processes taking place, the variety of species involved, and the range of length and time scales covered.•Many challenges remain for laser dicing of Si wafers primarily in three critical areas, i.e., ablation rate, ablation precision and quality, and die fracture strength.•Optimization of the ablation rate, ablation quality, and die fracture strength will require thorough consideration of all the influencing laser and process parameters in order to meet the requirements of the end product applications.
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